Series OSS Code No. 103
(Theory) Paper II
Time allowed : 3 hours Maximum Marks : 40
Instructions : Attempt all questions.
1. Draw a neat circuit diagram of a compound motor and give its applications. Explain how a compound motor combines the advantages of both shunt and series type of d.c. motors. 4+2+4
Explain why a starter is required for starting a d.c. shunt motor. Draw the connection diagram of a starter in conjunction with a d.c. shunt motor complete with protective devices. Write the function of protective devices. 4+4+2
2. (a) What is a diode ? What are its applications in half wave and full wave rectifiers ? Explain with diagrams. 1+2+2
(b) What is transistor ? What is its use in a voltage stabilizer ? 3
3. (a) Explain the difference between ordinary transformer and auto transformer. 4
(b) A 55 kVA, 11000 V/220 V, 50 Hz single-phase transformer has 50 turns on the secondary side. Determine 2+2+2
(i) number of turns on primary side
(ii) value of primary and secondary current at full load
(iii) transformation ratio
4. Describe the construction and principle of operation of a 1-pliase capacitor run Induction motor with neat sketches.
What are various faults which are likely to occur in a 1-phase Induction motor ? Write their remedies.